How accurate are TDEE calculators?

Mifflin-St Jeor BMR predicts true resting expenditure within about ±10% for healthy non-obese adults (Frankenfield et al., J Am Diet Assoc 2005). The activity multipliers add another layer of uncertainty because self-reported activity is notoriously biased upward. Expect the TDEE number to be within ±10-15% of reality and adjust from observed weight change over 2-4 weeks.

Why does the calculator split TDEE into BMR/TEF/NEAT/EAT?

These are the four components the energy-balance literature uses (Westerterp, IJBNPA 2004). Knowing the split makes it obvious that for most people, daily steps and posture (NEAT) move the dial far more than a 45-minute gym session (EAT). NEAT can vary by 300–800 kcal/day in the same person depending on their sedentary behavior.

My scale says I am not losing on a 500-kcal deficit. What did the calculator get wrong?

Probably the activity multiplier. If you said "moderately active" but actually sit most of the day with one workout, the real factor is closer to 1.375 — that is 200-300 kcal less TDEE than the calculator returned. Drop one activity tier and recompute. Also confirm food tracking is honest — un-logged sips, bites, and oils typically add 100-300 kcal/day.

Should I recompute TDEE as my weight changes?

Yes. BMR scales with body mass, so a 10 kg loss reduces BMR by roughly 100 kcal/day, and the activity multiplier also reduces because moving a smaller body costs fewer calories. Recompute every 4-6 kg of change or whenever a 4-week scale-trend stalls at the same calorie target.

How accurate are TDEE calculators?

Mifflin-St Jeor BMR predicts true resting expenditure within about ±10% for healthy non-obese adults (Frankenfield et al., J Am Diet Assoc 2005). The activity multipliers add another layer of uncertainty because self-reported activity is notoriously biased upward. Expect the TDEE number to be within ±10-15% of reality and adjust from observed weight change over 2-4 weeks.

Why does the calculator split TDEE into BMR/TEF/NEAT/EAT?

These are the four components the energy-balance literature uses (Westerterp, IJBNPA 2004). Knowing the split makes it obvious that for most people, daily steps and posture (NEAT) move the dial far more than a 45-minute gym session (EAT). NEAT can vary by 300–800 kcal/day in the same person depending on their sedentary behavior.

My scale says I am not losing on a 500-kcal deficit. What did the calculator get wrong?

Probably the activity multiplier. If you said "moderately active" but actually sit most of the day with one workout, the real factor is closer to 1.375 — that is 200-300 kcal less TDEE than the calculator returned. Drop one activity tier and recompute. Also confirm food tracking is honest — un-logged sips, bites, and oils typically add 100-300 kcal/day.

Should I recompute TDEE as my weight changes?

Yes. BMR scales with body mass, so a 10 kg loss reduces BMR by roughly 100 kcal/day, and the activity multiplier also reduces because moving a smaller body costs fewer calories. Recompute every 4-6 kg of change or whenever a 4-week scale-trend stalls at the same calorie target.

TDEE Calculator (Total Daily Energy Expenditure)

Total Daily Energy Expenditure broken into BMR, TEF, NEAT, and exercise.

Result

TDEE (maintain weight)

2,662 kcal/day

BMR — resting metabolism65% of TDEE — Mifflin-St Jeor1,718 kcal/day
TEF — thermic effect of food≈ 10% of TDEE for a mixed diet (Westerterp 2004)266 kcal/day
NEAT — non-exercise activityfidgeting, posture, walking, daily life475 kcal/day
EAT — exercise caloriesplanned workouts204 kcal/day
Maintenance targeteat this to hold weight2,662 kcal/day
Cutting target (−500 kcal/day)~1 lb / 0.45 kg per week loss2,162 kcal/day
Lean bulk (+250 kcal/day)~0.5 lb / 0.23 kg per week gain2,912 kcal/day

Sedentary (×1.2)

2,061 kcal/day

Lightly active (×1.375)

2,362 kcal/day

Moderately active (×1.55)

2,662 kcal/day

Very active (×1.725)

2,963 kcal/day

Extra active (×1.9)

3,263 kcal/day

Source: FAO/WHO/UNU Human Energy Requirements (2004) — activity factors; Mifflin-St Jeor (1990) — BMR

Not medical advice — TDEE is a population estimate (±10%). Real burn varies day to day with NEAT, thermogenesis, and training cost. Treat the number as a 7-day average and adjust based on 2-4 week scale trend.

How to use this calculator

Enter sex, age, weight, and height. Be honest about activity level — most people overestimate by one tier.
Read the TDEE number — that is your daily maintenance target.
Use the BMR/TEF/NEAT/EAT breakdown to see where your calories actually go. The biggest lever for almost everyone is NEAT (daily steps), not gym sessions.
For weight loss, use the cutting target (−500 kcal/day); for lean bulking, use the +250 kcal target.

About this tool

Total Daily Energy Expenditure (TDEE) is the calories you burn in 24 hours including everything — sleep, fidgeting, work, training, even digesting food. It is the single most useful number for weight management because hitting it maintains your weight, eating below it loses weight, and eating above it gains weight. This calculator decomposes TDEE into its four scientifically accepted components: BMR (resting metabolism, ~60-75%), TEF (thermic effect of food, ~10%), NEAT (non-exercise activity thermogenesis, 15-30%), and EAT (planned exercise, 5-15%). Most calorie counters return only a single TDEE number; the component view tells you which dial moves your daily burn the most.

What this calculator does

Estimates Total Daily Energy Expenditure and decomposes it into the four components used in the energy-balance literature: BMR (rest), TEF (digestion), NEAT (non-exercise movement), and EAT (planned exercise). Output rows below show maintenance, cutting (−500 kcal), and lean-bulk (+250 kcal) calorie targets calculated from your TDEE.

How it works — the formula

TDEE = BMR × activity factor
  BMR (Mifflin-St Jeor 1990):
    Men:   10·W(kg) + 6.25·H(cm) − 5·A(yr) + 5
    Women: 10·W(kg) + 6.25·H(cm) − 5·A(yr) − 161
  Activity factors (FAO/WHO/UNU 2004):
    Sedentary 1.2 · Light 1.375 · Moderate 1.55 · Very 1.725 · Extra 1.9

Component split (Westerterp 2004):
  TEF  ≈ 0.10 · TDEE
  NEAT + EAT = TDEE − BMR − TEF

BMR is multiplied by an activity factor to estimate TDEE — these factors were calibrated by FAO/WHO/UNU against doubly-labeled-water measurements across a range of populations. The thermic effect of food (TEF) for a typical mixed Western diet is approximately 10% of total daily intake (Westerterp). NEAT and EAT make up the rest of the above-BMR expenditure; this calculator splits them proportional to how far the chosen activity tier is above sedentary, on the assumption that "extra active" lifestyles concentrate more of their above-BMR calories in planned exercise.

Sources: FAO/WHO/UNU — Human Energy Requirements, Report of a Joint FAO/WHO/UNU Expert Consultation (Rome, 2004) · Mifflin MD et al. — A new predictive equation for resting energy expenditure in healthy individuals (Am J Clin Nutr 51(2):241–247, 1990) · Westerterp KR — Diet-induced thermogenesis (Nutr Metab (Lond) 1:5, 2004) · Frankenfield D et al. — Comparison of predictive equations for resting metabolic rate in healthy nonobese and obese adults (J Am Diet Assoc 105(5):775–789, 2005)

Worked examples

Example 1

Moderately active 30-year-old male

Inputs:: sex = male, age = 30, weight = 75 kg, height = 178 cm, activity = moderate (×1.55)
Output:: BMR ≈ 1,718 kcal/day → TDEE ≈ 2,663; TEF ≈ 266, NEAT ≈ 388, EAT ≈ 291

Cutting target (−500): 2,163 kcal/day. Lean bulk (+250): 2,913 kcal/day.

Example 2

Sedentary 40-year-old female office worker

Inputs:: sex = female, age = 40, weight = 65 kg, height = 165 cm, activity = sedentary (×1.2)
Output:: BMR ≈ 1,320 → TDEE ≈ 1,584; TEF ≈ 158, NEAT ≈ 106, EAT ≈ 0

A 500-kcal deficit would put intake at ~1,084 kcal/day — too aggressive. Add 6,000 daily steps to lift TDEE rather than cutting further.

Example 3

Very active 25-year-old male athlete

Inputs:: sex = male, age = 25, weight = 80 kg, height = 180 cm, activity = very active (×1.725)
Output:: BMR ≈ 1,830 → TDEE ≈ 3,157; TEF ≈ 316, NEAT ≈ 411, EAT ≈ 600

EAT > NEAT for this profile — typical for someone training 6 days/week with otherwise normal daily activity.

When to use this vs other tools

TDEE is the maintenance number. If you only want the rest-only baseline or only the calorie deficit math, the sibling tools below are more focused.

BMR Calculator
You only need resting metabolic rate (calories at complete rest), not total daily burn.
Calorie Calculator
You want a calorie target focused on weight-management goals (cut, maintain, lean bulk) without the four-component breakdown.
Macro Calculator
You already know your TDEE and need to split it into protein, carbs, and fat.
Protein Calculator
You only need a daily protein target — typically 1.6–2.2 g/kg for active adults.

Authority note

FAO / WHO / UNU

Human Energy Requirements, Report of a Joint FAO/WHO/UNU Expert Consultation (Rome, 2004)

The activity multipliers used here (1.2 → 1.9) are the Physical Activity Level (PAL) values defined and calibrated by the FAO/WHO/UNU consultation against doubly-labeled-water reference measurements.

Limitations

Self-reported activity level is notoriously biased upward. If actual results disagree with the calculator after 4 weeks, the most likely explanation is being one activity tier lower than chosen.
The BMR/TEF/NEAT/EAT split is a heuristic decomposition; only BMR + total TDEE are directly predicted. The TEF share assumes a mixed diet — very high-protein diets push TEF toward 15-25% of intake.
Adaptive thermogenesis after sustained dieting can suppress real TDEE 5-15% below the predicted value for months after weight loss — recompute and possibly drop a tier after extended deficits.
Pregnancy, lactation, fever, hyperthyroidism, hypothyroidism, and recent significant weight change all shift TDEE outside the predicted range. The calculator does not detect these states.

Calorie targets are starting points, not prescriptions. Adjust based on 2-4 weeks of actual weight trend. This calculator does not provide medical, dietetic, or weight-management advice — consult a registered dietitian or physician for clinical needs.

Frequently asked

BMR is calories burned at complete rest. TDEE is BMR plus the thermic effect of food (TEF), non-exercise activity thermogenesis (NEAT), and exercise activity thermogenesis (EAT). TDEE is the number to eat at for weight maintenance; eating only at BMR usually creates an unintentionally aggressive deficit.